The link between celiac disease (a disorder in which the body has an allergic response to a gluten found in grains, leading to damage of the absorbant villi fingers that line the intestinal tract) and schizophrenia is suggestive, but questionable. If there is such a link, celiac disease certainly does not cause the symptoms of schizophrenia for more than a handful of individuals, given the low incidence of both disorders. Moreover, some research has suggested that for at-risk children (with a family history of celiac disease), delaying exposure to grain products for the first six months of life may reduce the chances of developing the allergic symptoms. This may play a small role in reducing that child's chance of developing schizophrenia.

One large study of 7,997 Danish citizens (Eaton et al, 2004) who were admitted to health facilities with a diagnosis of schizophrenia between 1981 and 1998, found that four patients and eight parents of patients were being treated for celiac disease symptoms. The authors calculated an incidence of 1.5 cases of celiac disease per 1000 people in this population, as compared to a 0.5 incidence of celiac disease in the control population. Based on this data, the authors suggested a 3-fold increased risk of schizophrenia symptoms in an individual with celiac disease, over that of an individual in the general population (relative risk of schizophrenia for general population is 1%). It is important to note, however, that there is a fair amount of dissent about the above conclusions. Campbell and Foley (2004) commented in a later edition of the British Journal of Medicine that the "data do not support the hypothesis" of the Danish study cited above. They believe that parents of people with schizophrenia should not be included in the total cases of celiac disease for that population. "If the parents' data are excluded from the analysis the prevalence of coeliac disease in people with new onset schizophrenia is only 0.5 per 1000, which is the same as in their control group." (Campbell and Foley, 2004).

Another article (Wei 2005) commented on the possible genetic link between celiac disease and schizophrenia (the genetic marker of celiac disease is close to the disbindin gene locus, a gene that may be linked to schizophrenia - thus the two loci may have a higher probability of being inherited together), and hypothesized that for individuals with celiac disease, the abnormal gut permeability that is characteristic of the disorder may contribute to schizophrenia symptoms by causing malnutrition (significantly decreased absorption of key vitamins and nutrients - vitamin D deficiency has been linked to schizophrenia), or by allowing greater amounts of psychosis-inducing toxins to enter the body.

Helpful Actions: Although the possibility of celiac disease contributing to schizophrenia is small, it may be important to identify those few individuals for whom such a link might exist.

If you have a history of celiac disease in your family, you may want to take extra precautions to try and protect your children from developing the intestinal damage that results from the manifestation of the disease. Although it is not clear whether a slightly higher incidence of celiac disease in people with schizophrenia might be because of close gene loci for the two disorders, or because the intestinal damage from celiac disease contributes to the risk for schizophrenia from environmental factors, it may be wise to take precautions.

A BBC News article from July 2005 reported that infants may have a reduced chance of developing celiac disease if their diets do not include grains until 4-6 months of age. Researchers quoted in the article calculated that in children who had a family history of celiac disease, those who were exposed to glutens within the first three months of life had a five-fold increased risk of developing the allergic reaction themselves. There was no reported benefit to withholding gluten for longer than the first six months.

The researchers hypothesized that a "sensitive period" may exist during which the gut barrier is not fully developed, allowing larger amounts of glutens to cross from inside the intestines and evoke an allergic response from the body's immune system. However, the authors also cautioned: ""We cannot exclude the possibility that earlier exposure to gluten simply leads to earlier appearance of disease and that all exposed at-risk children will eventually develop coeliac disease."